Duchenne Muscular Dystrophy, DMD, is a genetic disorder in which a person's muscles progressively become weaker over time eventually resulting in complete loss of muscle functioning. The disease is mostly present in males beginning around the age of 4 and by the age of 12, children will have to use a wheelchair. Along with its severe muscle damaging, DMD may also affect a child's learning, memory, communication, and social skills. The muscle weakness starts in the pelvic area hips, legs and shoulders and will eventually attack the heart muscles and respiratory system which is when the disease becomes detrimental. The cause for this disease is due to the absence of a protein that is used to keep the muscles functioning known as dystrophin. (1)
This visual display shows the areas of the body where DMD will begin to cause weakness:
Clumsiness, trouble climbing stairs or getting off the floor
waddling or walking on toes
scoliosis
Trouble concentrating
poor memory
In infancy, delayed ability to walk or stand
To elaborate, scoliosis is a disorder that can be considered its own condition but can also be caused by muscular dystrophy and results in a sideways curvature of the spine. In severe cases, scoliosis will become painful (2) Furthermore, since most symptoms of DMD appear in young children, possibly occurring as early as infancy, it may be difficult for these children to express their emotions. Therefore, parents are usually the ones who must watch for and report symptoms. Additionally, people suffering from DMD usually do not survive out of their teenage years as at 18 years, the disease usually becomes fatal. However, more recently, people have been reported to survive into their 30s. In cases where the disease is not as aggressive, people may even be able to live into their 40s. (3)
A diagram showing the motion of the spine with scoliosis compared to a normal spine:
The gene for DMD is a recessive allele occuring when a mutation forms on a gene on the X chromosome preventing the formation of dystrophin. Dystrophin is a protein found throughout muscle cells and is vital in the strengthening of muscles as well as protecting muscles from injury (5). This disorder is sex-linked and is much more common in boys as opposed to girls. This is because boys are given an X chromosome from the mother and a Y from the father, whereas girls are given two Xs. Since dystrophin can only be found on the X chromosome, when the DMD-causing mutation forms subsequently preventing dystrophin from being present, a boy cannot get the dystrophin needed from the other X chromosome and therefore will definetly have DMD. However, a girl can have the mutation on one X chromosome yet still produce the dystrophin from her other X chromosome, which would prevent the DMD gene from causing any effects. In this case, one would be considered a carrier for the disorder. (4)
Distribution:
DMD affects 1 in 7,250 males aged 5-24. The disorder is prevalent among boys because the mutation for DMD only has to appear on their X chromosome, whereas a girl must have an altered copy of the gene for dystrophin on both Xs which is highly unlikely(4) Because the disease rapidly affects muscles throughout a human's body, symptoms are usually present during early childhood or when a child begins to walk. DMD is not more prominent in some ethnicities, races, or areas of the world more than others as the mutation can form despite the instance of having no family members with the disorder, therefore giving all children an equal chance of developing DMD. (6)
Treatment:
With daily medical and technological advances, people with DMD are living longer than any previous generation. Anesthesia is commonly used to relieve pain but different types of it can cause unexpected reactions. New born babies with DMD should get their hearts checked. It is recommended to get their hearts checked at least every other year until the age of 10. According to mda org, female carriers of DMD are at higher-than-average risk of developing cardiomyopathy. Complete cardiac evaluation should start at 25 (or sooner if symptoms occur early) and be done every 5 years. (1)
Miscellaneous:
Rapper and disability rights activist Darius Weems suffered from DMD and used his publicity to raise awareness to find a cure for his disease. In 2007, a documentary was was released called Darius Goes West which illustrated his life having to live with DMD. Weems passed away from the disease in 2016 at the age of 27. (7)
In this video, Weems describes his life with DMD as well as his attempts to find a cure:
Society and culture:
History:
DMD derives from the French neurologist Guillaume-Benjamin-Amand Duchenne, who first suggested the disease after writing a book in 1861 which described a boy with the condition. Duchenne additionally published a book in 1868 that illustrated pictures of his affected patients (8). Over time, scientists and researchers became more knowledgable on the cause of DMD. Among the discovery of DMD, little was known about its cause until the 1980s when members of the Muscular Dystrophy Asscoiation discovered a gene on the X chromosome that, if mutated, triggered the onset of both Duchenne and Becker muscular dystrophies (1)
Further Research:
CureDuchenne is the first FDA, drug approved DMD charity. They have funded 9 research projects and have advanced to human clinical trials.
Meet Alex Chiabai – First Boy in Canada to Begin Drisapersen Redosing: Website
Donate here: Donation
Duchenne Muscular Dystrophy
Overview:
Duchenne Muscular Dystrophy, DMD, is a genetic disorder in which a person's muscles progressively become weaker over time eventually resulting in complete loss of muscle functioning. The disease is mostly present in males beginning around the age of 4 and by the age of 12, children will have to use a wheelchair. Along with its severe muscle damaging, DMD may also affect a child's learning, memory, communication, and social skills. The muscle weakness starts in the pelvic area hips, legs and shoulders and will eventually attack the heart muscles and respiratory system which is when the disease becomes detrimental. The cause for this disease is due to the absence of a protein that is used to keep the muscles functioning known as dystrophin.
(1)
This visual display shows the areas of the body where DMD will begin to cause weakness:
(1)
Signs and Symptoms:
(1)
To elaborate, scoliosis is a disorder that can be considered its own condition but can also be caused by muscular dystrophy and results in a sideways curvature of the spine. In severe cases, scoliosis will become painful (2) Furthermore, since most symptoms of DMD appear in young children, possibly occurring as early as infancy, it may be difficult for these children to express their emotions. Therefore, parents are usually the ones who must watch for and report symptoms. Additionally, people suffering from DMD usually do not survive out of their teenage years as at 18 years, the disease usually becomes fatal. However, more recently, people have been reported to survive into their 30s. In cases where the disease is not as aggressive, people may even be able to live into their 40s. (3)
A diagram showing the motion of the spine with scoliosis compared to a normal spine:
Genetics:
The gene for DMD is a recessive allele occuring when a mutation forms on a gene on the X chromosome preventing the formation of dystrophin. Dystrophin is a protein found throughout muscle cells and is vital in the strengthening of muscles as well as protecting muscles from injury (5). This disorder is sex-linked and is much more common in boys as opposed to girls. This is because boys are given an X chromosome from the mother and a Y from the father, whereas girls are given two Xs. Since dystrophin can only be found on the X chromosome, when the DMD-causing mutation forms subsequently preventing dystrophin from being present, a boy cannot get the dystrophin needed from the other X chromosome and therefore will definetly have DMD. However, a girl can have the mutation on one X chromosome yet still produce the dystrophin from her other X chromosome, which would prevent the DMD gene from causing any effects. In this case, one would be considered a carrier for the disorder. (4)
Distribution:
DMD affects 1 in 7,250 males aged 5-24. The disorder is prevalent among boys because the mutation for DMD only has to appear on their X chromosome, whereas a girl must have an altered copy of the gene for dystrophin on both Xs which is highly unlikely(4) Because the disease rapidly affects muscles throughout a human's body, symptoms are usually present during early childhood or when a child begins to walk. DMD is not more prominent in some ethnicities, races, or areas of the world more than others as the mutation can form despite the instance of having no family members with the disorder, therefore giving all children an equal chance of developing DMD. (6)
Treatment:
With daily medical and technological advances, people with DMD are living longer than any previous generation. Anesthesia is commonly used to relieve pain but different types of it can cause unexpected reactions. New born babies with DMD should get their hearts checked. It is recommended to get their hearts checked at least every other year until the age of 10. According to mda org, female carriers of DMD are at higher-than-average risk of developing cardiomyopathy. Complete cardiac evaluation should start at 25 (or sooner if symptoms occur early) and be done every 5 years.
(1)
Miscellaneous:
Rapper and disability rights activist Darius Weems suffered from DMD and used his publicity to raise awareness to find a cure for his disease. In 2007, a documentary was was released called Darius Goes West which illustrated his life having to live with DMD. Weems passed away from the disease in 2016 at the age of 27. (7)
In this video, Weems describes his life with DMD as well as his attempts to find a cure:
Society and culture:
History:
DMD derives from the French neurologist Guillaume-Benjamin-Amand Duchenne, who first suggested the disease after writing a book in 1861 which described a boy with the condition. Duchenne additionally published a book in 1868 that illustrated pictures of his affected patients (8). Over time, scientists and researchers became more knowledgable on the cause of DMD. Among the discovery of DMD, little was known about its cause until the 1980s when members of the Muscular Dystrophy Asscoiation discovered a gene on the X chromosome that, if mutated, triggered the onset of both Duchenne and Becker muscular dystrophies (1)
Further Research:
CureDuchenne is the first FDA, drug approved DMD charity. They have funded 9 research projects and have advanced to human clinical trials.
Meet Alex Chiabai – First Boy in Canada to Begin Drisapersen Redosing:
Website
Donate here:
Donation
Other Pages:
Sex-Linked Genetic Disorders
Hemophilia (website for another type of sex-linked genetic disorder)
References:
(1) “Duchenne Muscular Dystrophy (DMD).” Muscular Dystrophy Association, 13 Apr. 2018, www.mda.org/disease/duchenne-muscular-dystrophy
(2) “Scoliosis.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 29 Dec. 2017, __www.mayoclinic.org/diseases-conditions/scoliosis/symptoms-causes/syc-20350716__. (3 “Understanding Muscular Dystrophy -- the Basics.” WebMD, WebMD,
__www.webmd.com/children/understanding-muscular-dystrophy-basics#1__.
(4)“Learning About Duchenne Muscular Dystrophy.” National Human Genome Research Institute (NHGRI), __www.genome.gov/19518854/learning-about-duchenne-muscular-dystrophy/__.
(5)“Understanding the Role of Dystrophin in Duchenne.” Duchenne, __www.duchenne.com/importance-of-dystrophin__.
(6)DuchenneConnect, Admin At. “The Duchenne Registry.” Genetic Causes, __www.duchenneregistry.org/about-duchenne-becker/genetic-causes.html__.
(7)Mcfadden, Cynthia, et al. “Darius Weems' Next Chapter: Rap Star With Duchenne Muscular Dystrophy Tries Clinical Trial.” ABC News, ABC News Network, 22 Nov. 2012, abcnews.go.com/Health/darius-weems-chapter-rap-star-duchenne-muscular-dystrophy/story?id=17779732.
(8)“Guillaume Benjamin Amand Duchenne De Boulogne.” Whonamedit - Dictionary of Medical Eponyms, __www.whonamedit.com/doctor.cfm/950.html__.